The term blister pack refers to non-reclosable, typically clear plastic packaging commonly used for unit-dose packaging for pharmaceutical dosage forms such as tablets, capsules or lozenges. Blister packs provide a degree of protection where product tampering is a consideration by way of product/packaging integrity. In the United States, blister packs are mainly used for packing physician samples of drug products or for the sale of Over The Counter (OTC) products in the pharmacy.
Blister packs are typically created by means of a form-fill-seal process in which the blister pack is created from rolls of flat sheet or film (made of a plastic material such as polypropylene), filled with the pharmaceutical product and closed (sealed) on the same equipment (typically called a blisterline). Blister packs include two principle components: (1) a formed base which includes the cavities inside which the products fit, and (2) a sealing rupture foil or film (made of, for example, an aluminum foil) which covers the cavities for dispensing the product out of the pack. The blister pack may also include a plastic or paper foil disposed over the sealing foil wherein the attachment between the plastic or paper foil and the sealing foil is stronger that the attachment between the sealing foil and the base so that a portion of the sealing foil (i.e., covering one of the cavities) may be removed as desired.
A typical prior art blister pack 90 is shown in FIGS. 10 (isometric view showing the base side) and 11 (bottom plan view showing the dispensing side). The blister pack 90 includes a base 95 having a plurality of cavities 100 formed therein into which tablets 105 are inserted, and a sealing sheet 110 (which may comprise a number of different layers of material) which covers the base 95. The sealing sheet 110 often includes a foil layer made of a metallic material such as aluminum foil, and may be covered by a covering layer made of a material such as paper.
Key concerns with blister packs that are used in the pharmaceutical industry are tampering and counterfeiting. In particular, with counterfeiting, a counterfeiter may try to open the blister pack and replace the original product with a counterfeit product, or may try to duplicate the blister pack in its entirety. To address these concerns among others, the FDA is likely going to require chain of custody tracking for a variety of pharmaceutical products. There is thus a need for techniques for improving the ability to detect and prevent tampering and counterfeiting and facilitating chain of custody tracking in situations where blister packs are employed.